The computer files at the heart of the case against the former Los Alamos scientist Wen Ho Lee were given higher security classifications last year only after he was fired in the midst of an espionage investigation at the weapons laboratory, say defense lawyers and federal officials.
At the time Lee downloaded the files onto his computer, they were classified but not designated secret or confidential, as the indictment against him alleges. Instead, they were governed by a lower kind of security precaution, according to both sides in the case, as well as a document that federal prosecutors filed as evidence.
Mark Holscher, the lead lawyer for Lee, said the after-the-fact change, which he said his team discovered while studying prosecution evidence, would be a powerful weapon for the defense. But Holscher would not say how he intended to use it, beyond declaring, ``The indictment is deceptive.''
Though government officials conceded that the original security level was low, they emphatically denied that the material Lee downloaded was insignificant.
``We stand by our indictment and look forward to litigating this issue when Dr. Lee is tried,'' said Myron Marlin, a Justice Department spokesman. ``What Lee stole was the crown jewels.''
On Monday, the Albuquerque Journal reported the low security classification for the downloaded data.
Since his indictment December 10, Lee has been held without bail, in solitary confinement and under unusually tight security in Santa Fe, N.M.
Federal prosecutors have accused him of seizing the heart of the American nuclear arsenal, but his backers maintain that his actions were nothing out of the ordinary and that he is being singled out because of his ethnic background. A native of Taiwan, Lee is a naturalized U.S. citizen.
The downloaded material had a security designation ``protect as restricted data,'' or PARD, a category applied to scientific data so voluminous and changing so frequently as to be impossible to assess in terms of security. It is not a security classification per se, but rather a rule for handling potentially sensitive materials and is governed by the secrecy provisions of the nation's atomic energy laws.
While PARD material by definition is classified and the designation holds out the possibility that some of it might be highly sensitive, it is not subject to the same stringent precautions applied to data designated secret or confidential. For example, scientists working with it may leave it on their desks overnight, rather than in a safe.
Still, PARD data must be kept in secure premises at the weapons laboratory; by law it cannot be transferred onto unsecured computers, as the government has charged Lee with doing.
A federal official familiar with the legalities of the case who strongly supports the government's position said the downloaded data included computer instructions on how to simulate the design of a nuclear warhead, including exact dimensions and other geometrical information that, when standing alone, would be guarded assiduously.
A senior administration weapons expert strongly contested the idea that the data in the Lee indictment was any less important than more concentrated data on nuclear arms.
The defense team countered, though, that any critical information was buried in a virtually indecipherable mass of benign data.
Commenting on the dispute, Steven Aftergood, a secrecy and classification expert at the Federation of American Scientists, a private group in Washington, said the development would throw the government on the defensive.
``This takes some of the heat off Wen Ho Lee and puts it on the government, and particularly on the security system,'' Aftergood said.